Abstracts

Rationale: Children with secondary generalized epilepsy are good candidates for vagus nerve stimulation. Little data is available regarding the effect of prolonged vagus nerve stimulation, especially regarding the potential long-term permanent neuromodulatory potential of the therapy. We studied patients who were submitted to VNS and in whom there was battery depletion. Methods: Six children under the age of 12 years with secondary generalized epilepsy who were submitted to vagus nerve stimulation for at least seven years, initially benefitted from the procedures and who remained with their battery depleted for at least six months were studied. Pre- and post-depletion seizure frequency was recorded in a seizure diary. Results: In five out of the 6 children there was worsening of the seizure frequency by the time of vagus nerve stimulator battery depletion: seizure frequency tripled in two kids, quadruplicated in one, reappeared in one, and got daily and uncountable in one. In one child seizure frequency was unaltered after battery depletion. Conclusions: Long-term vagus nerve stimulation did not lead to permanent neuromodulatory effects. Patients who responded to VNS might need to keep the device operational to benefit from sustained seizure frequency reduction.